使用 Java 解密 OpenSSL PEM 编码的 RSA 私钥? [英] Decrypting an OpenSSL PEM Encoded RSA private key with Java?
问题描述
我有一个加密的私钥并且我知道密码.
I have an encrypted private key and I know the password.
我需要使用 Java 库对其进行解密.
I need to decrypt it using a Java library.
不过，除非别无选择，否则我不希望使用 BouncyCastle.根据之前的经验，变化太多，文档不够.
I'd prefer not to use BouncyCastle though, unless there is no other option. Based on previous experience, there is too much change and not enough documentation.
私钥采用这种形式:
-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,56F3A98D9CFFA77A
X5h7SUDStF1tL16lRM+AfZb1UBDQ0D1YbQ6vmIlXiK....
.....
/KK5CZmIGw==
-----END RSA PRIVATE KEY-----
我相信关键数据是 Base64 编码的，因为我在 64 个字符后看到
.
I believe the key data is Base64 encoded since I see
after 64 characters.
我尝试了以下方法来解密密钥:
I tried the following to decrypt the key:
import java.security.Key;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.EncryptedPrivateKeyInfo;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
public String decrypt(String keyDataStr, String passwordStr){
// This key data start from "X5... to =="
char [] password=passwordStr.toCharArray();
byte [] keyDataBytes=com.sun.jersey.core.util.Base64.decode(keyDataStr);
PBEKeySpec pbeSpec = new PBEKeySpec(password);
EncryptedPrivateKeyInfo pkinfo = new EncryptedPrivateKeyInfo(keyDataBytes);
SecretKeyFactory skf = SecretKeyFactory.getInstance(pkinfo.getAlgName());
Key secret = skf.generateSecret(pbeSpec);
PKCS8EncodedKeySpec keySpec = pkinfo.getKeySpec(secret);
KeyFactory kf = KeyFactory.getInstance("RSA");
PrivateKey pk=kf.generatePrivate(keySpec);
return pk.toString();
}
我收到此异常
java.io.IOException: DerInputStream.getLength(): lengthTag=50, too big.
at sun.security.util.DerInputStream.getLength(DerInputStream.java:561)
at sun.security.util.DerValue.init(DerValue.java:365)
at sun.security.util.DerValue.<init>(DerValue.java:294)
at javax.crypto.EncryptedPrivateKeyInfo.<init> (EncryptedPrivateKeyInfo.java:84)
我是否将正确的参数传递给了 EncryptedPrivateKeyInfo 构造函数?
Am I passing the right parameter to EncryptedPrivateKeyInfo constructor?
我怎样才能做到这一点?
How can I make this work?
我尝试了 Ericsonn 的建议，做了一个小改动，因为我使用的是 Java 7，我无法使用 Base64.getMimeCoder() 而是使用 Base64.decode 并且出现此错误在 com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:750)
I tried what Ericsonn suggested, with one small change since I am working Java 7, I could not use Base64.getMimeCoder() instead I used Base64.decode and I am getting this error I am getting an error like this Input length must be multiple of 8 when decrypting with padded cipher at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:750)
static RSAPrivateKey decrypt(String keyDataStr, String ivHex, String password)
throws GeneralSecurityException, UnsupportedEncodingException
{
byte[] pw = password.getBytes(StandardCharsets.UTF_8);
byte[] iv = h2b(ivHex);
SecretKey secret = opensslKDF(pw, iv);
Cipher cipher = Cipher.getInstance("DESede/CBC/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
byte [] keyBytes=Base64.decode(keyDataStr.getBytes("UTF-8"));
byte[] pkcs1 = cipher.doFinal(keyBytes);
/* See note for definition of "decodeRSAPrivatePKCS1" */
RSAPrivateCrtKeySpec spec = decodeRSAPrivatePKCS1(pkcs1);
KeyFactory rsa = KeyFactory.getInstance("RSA");
return (RSAPrivateKey) rsa.generatePrivate(spec);
}
private static SecretKey opensslKDF(byte[] pw, byte[] iv)
throws NoSuchAlgorithmException
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
md5.update(pw);
md5.update(iv);
byte[] d0 = md5.digest();
md5.update(d0);
md5.update(pw);
md5.update(iv);
byte[] d1 = md5.digest();
byte[] key = new byte[24];
System.arraycopy(d0, 0, key, 0, 16);
System.arraycopy(d1, 0, key, 16, 8);
return new SecretKeySpec(key, "DESede");
}
private static byte[] h2b(CharSequence s)
{
int len = s.length();
byte[] b = new byte[len / 2];
for (int src = 0, dst = 0; src < len; ++dst) {
int hi = Character.digit(s.charAt(src++), 16);
int lo = Character.digit(s.charAt(src++), 16);
b[dst] = (byte) (hi << 4 | lo);
}
return b;
}
static RSAPrivateCrtKeySpec decodeRSAPrivatePKCS1(byte[] encoded)
{
ByteBuffer input = ByteBuffer.wrap(encoded);
if (der(input, 0x30) != input.remaining())
throw new IllegalArgumentException("Excess data");
if (!BigInteger.ZERO.equals(derint(input)))
throw new IllegalArgumentException("Unsupported version");
BigInteger n = derint(input);
BigInteger e = derint(input);
BigInteger d = derint(input);
BigInteger p = derint(input);
BigInteger q = derint(input);
BigInteger ep = derint(input);
BigInteger eq = derint(input);
BigInteger c = derint(input);
return new RSAPrivateCrtKeySpec(n, e, d, p, q, ep, eq, c);
}
private static BigInteger derint(ByteBuffer input)
{
byte[] value = new byte[der(input, 0x02)];
input.get(value);
return new BigInteger(+1, value);
}
private static int der(ByteBuffer input, int exp)
{
int tag = input.get() & 0xFF;
if (tag != exp)
throw new IllegalArgumentException("Unexpected tag");
int n = input.get() & 0xFF;
if (n < 128)
return n;
n &= 0x7F;
if ((n < 1) || (n > 2))
throw new IllegalArgumentException("Invalid length");
int len = 0;
while (n-- > 0) {
len <<= 8;
len |= input.get() & 0xFF;
}
return len;
}
1640 是 keyDataStr.length()，1228 是 keyBytes.length
1640 is keyDataStr.length() and 1228 is keyBytes.length
推荐答案
您需要使用非标准的 OpenSSL 方法来导出解密密钥.然后用它来解密 PKCS-#1–编码的密钥—你正在使用的是不是一个 PKCS #8 信封.您还需要来自标题的 IV 作为这些进程的输入.
You need to use a non-standard, OpenSSL method for deriving the decryption key. Then use that to decrypt the PKCS-#1–encoded key—what you are working with is not a PKCS #8 envelope. You'll also need the IV from the header as input to these processes.
看起来像这样:
static RSAPrivateKey decrypt(String keyDataStr, String ivHex, String password)
throws GeneralSecurityException
{
byte[] pw = password.getBytes(StandardCharsets.UTF_8);
byte[] iv = h2b(ivHex);
SecretKey secret = opensslKDF(pw, iv);
Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
byte[] pkcs1 = cipher.doFinal(Base64.getMimeDecoder().decode(keyDataStr));
/* See note for definition of "decodeRSAPrivatePKCS1" */
RSAPrivateCrtKeySpec spec = decodeRSAPrivatePKCS1(pkcs1);
KeyFactory rsa = KeyFactory.getInstance("RSA");
return (RSAPrivateKey) rsa.generatePrivate(spec);
}
private static SecretKey opensslKDF(byte[] pw, byte[] iv)
throws NoSuchAlgorithmException
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
md5.update(pw);
md5.update(iv);
byte[] d0 = md5.digest();
md5.update(d0);
md5.update(pw);
md5.update(iv);
byte[] d1 = md5.digest();
byte[] key = new byte[24];
System.arraycopy(d0, 0, key, 0, 16);
System.arraycopy(d1, 0, key, 16, 8);
return new SecretKeySpec(key, "DESede");
}
private static byte[] h2b(CharSequence s)
{
int len = s.length();
byte[] b = new byte[len / 2];
for (int src = 0, dst = 0; src < len; ++dst) {
int hi = Character.digit(s.charAt(src++), 16);
int lo = Character.digit(s.charAt(src++), 16);
b[dst] = (byte) (hi << 4 | lo);
}
return b;
}
这已经是很多代码了，所以我将链接到另一个关于decodeRSAPrivatePKCS1()<的定义的答案/code> 方法.
This is already a lot of code, so I will link to another answer for the definition of the decodeRSAPrivatePKCS1() method.
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